Question Detail
Question
There are 10 points on a circle. By joining them, how many chords can be drawn?
Correct Answer
Option C is the correct answer.
Detailed Explanation
A chord is formed by joining any two distinct points on a circle. The order in which the two points are chosen does not matter (joining point P to Q is the same as joining Q to P). Therefore, this is a combination problem. We need to choose 2 points out of 10. The formula for combinations is C(n, r) = n! / (r! * (n-r)!). Here, n=10 and r=2. So, C(10, 2) = (10 * 9) / (2 * 1) = 45 chords.
Hint
A chord is defined by two points, and the order of selection does not matter.